Multiple distribution system



w. J. HERDMAN 2,188,508

' MULTIPLE DISTRIBUTION SYSTEM Jan. 30, 1940.

Filed Sept. l5, 1937 PRIMARY RECEIVER SECONDARY RECEIVERS I 2/6 PRl MARY RECEIVER I i SECONDARY RECEIVERS a AMP. MDD.

H w 4 6 8 FREOUENOY MASTER u GENERATOR "osclLLA-rolz II V5 II k E 4 3 i AMP.- MQD. 5 v4 -l \9 I f E-g; I JNVENTOR. L 84 POWER SOURCE By ATTORN Patented Jan. 30, 1940 PATENT OFFICE MULTIPLE DISTRIBUTION SYSTEM William J. Herdman, South Orange, N. .L, assignor to Wired Radio, Inc., New York, N. Y., a corporation of Delaware Application September 15, 1937, Serial No. 163,934

1 Claim.

This invention pertains in general to signal distribution systems and specifically relates to a system of wired radio distribution.

The principal object of the invention consists in providing a system for impressing signalling energy at a plurality of points of an electrical distribution system so as to produce uniform and economical distribution of signalling energy to a multiplicity of receiving points coupled with the network.

A further object comprises providing a system for conjointly distributing signalling energy and commercial power to a multiplicity of receiving points, the signalling energy being high frequency 16 energy over a portion of the distribution area and being audio frequency energy over another portion of the distribution area.

A further object of the invention comprises providing a multiple distribution system for 20 transmitting signals as carrier energy to a plurality of re-distribution points at which points the signalling energy is amplified and converted into a different frequency range and further distributed to a multiplicity of ultimate receiving 25 points for selective reception thereat.

Astill further object of the invention comprises providing a selective program reception system having means for transmitting plural program-channel signalling energy to remote 30 points for conversion into plural channel audiofrequency energy for further transmission to remote reception points.

These and other objects will be apparent from the following, reference being had to the accom- 85 panying drawing in which the single figure is a wiring diagram illustrating one embodiment of the invention, the connected apparatus being shown in block form.

The invention contemplates a system for effect- 4 ing a uniform, efficient and economical distribution of multiple programs to a multiplicity of receiving points. In the present instance, these receiving points are described in connection with a building such as an apartment house or hotel,

45 but the inventive concept may be applied to equivalent distribution situations involving like conditions.

In accordance with the invention, a plurality of carrier frequencies are generated from a base 50 frequency, and these carrier frequencies are modulated with different program modulation frequencies. The resultant modulated carrier frequencies are simultaneously impressed upon a power distribution network. The power distribu- 55 tion network conjointly transmits plural program signalling energy and commercial power to a plurality of primary receivers, each of which serves a restricted distribution area.

The primary receivers conjointly receive commercial power, for producing electron-tube operating-voltages, and the plural program carrier frequency signalling energy. The signalling energy is amplified and delivered to a plurality of different converters included in the primary receivers. Each of the converters includes suit- 10 able equipment for amplifying and detecting the carrier frequency energy of a particular program channel, thus effecting an amplified frequency conversion of the program to the audio frequency range. All of the converters of each primary receiver are connected with a cable extending to secondary receivers for selective reproduction of a program transmitted over the cable.

Referring to the drawing in detail, power source I generates commercial power such as 60-cyc1e alternating current which is fed to the distribution network 2 having branch circuit lines A and B. The branch circuits A and B, for example, may be on different floors of an apartment house, hotel or the like.

A master oscillator 3 produces a base carrier frequency, such as 13 kilocycles. The output of the master oscillator '3 is delivered to a frequency generator 4 which develops a plurality of harmonically related discrete carrier frequencies. For example, the circuit 5 carries a frequency of 26 kilocycles, the circuit 6 carries a frequency of 39 kilocycles, and the circuit I carries a frequency of 52 kilocycles. The circuits 5 to 1 connect with modulators 9, l0 and II. The modula- 5 tors 9, I0 and H each include difierent sources of modulation frequencies and means for modulating the carrier frequency delivered to each modulator in accordance with the modulation frequency. The outputs of the modulators 9 to II are respectively delivered to amplifiers M to IS. The amplifiers M to I6 each include suitable amplification equipment and band pass filters for the side band ranges adjacent the respective carrier frequencies. The outputs of the amplifiers I l-I6 are impressed upon the network 2 through capacitive couplings II. All of the foregoing signal units are connected with a power energizing circuit including signal blockers 8a and 8b, which block the back-feed of signalling energy but permit the free passage of commercial alternating current.

In accordance with the invention, a primary receiver is connected with the circuit A and includes an amplifier 20 having conductive power connections and capacitive signalling energy connections with the branch circuit A. Amplifier 20 has a broad frequency pass range for amplifying all of the various carrier frequencies and their attendant side bands as transmitted over the power network 2. Converters 2I--23 are connected with the amplifier 20, and each includes a band pass filter for admitting the frequencies corresponding to a particular program channel. The band pass filter of each converter is connected with suitable amplifier and detector equipment for producing a frequency conversion from the carrier frequency range to the audio frequency range, with desired amplification. The outputs of the converters 2l23 are all amplified audio frequency ranges, corresponding in frequencies to the original modulation frequencies utilized at the modulators 9-1 I. The outputs of the converters 2l23 are delivered to individual pairs of a cable coextensive with the branch circuit A.

A plurality of secondary receivers 25 and 21 are coupled with the branch circuit A and cable 25. Each of the secondary receivers 28 and 21 may comprise merely a loud speaker with suitable armature and field producing means. Again, the secondary receivers 26 and 21 may be more elaborate when desired and include, in addition, amplification equipment. Operating voltages for the power consuming devices in the receivers 26 and 21 are derived from circuits extending to the branch circuit A and include signal blocking devices 29 and 30. The signal blocking devices 29 and 30 permit the commercial alternating current to pass to the receivers but prevent the passage of disturbing signalling energy to the receivers.

The signal input circuits for the receivers 26 and 21 include selector switches 3| and 32 having selector contacts connected with the different pairs of the cable 25. These switches 3| and 32 at the different secondary receivers may be manually moved to engage any of the contacts so as to selectively receive the different frequency channels. The program signals are then suitably reproduced at the secondary receivers.

The branch circuit B is provided with suitable equipment as described in connection with the branch circuit A, such equipment being designated by corresponding reference numerals with the addition of the letter b. Where desirable, the cable 25 and branch circuit A may be incorporated in a single shielded exterior cable structure for constructional purposes.

Although a preferred form of multiple distribution system has been disclosed, it will be realized that various changes and equivalent structures will occur to those skilled in the art but which will not depart from the intended scope of the invention. Therefore, no limitation is intended except as imposed by the appended claim.

What is claimed as new and original to be secured by Letters Patent of the United States In a given space having a power distribution system, the method of distributing programs from a common point to a multiplicity of receiving points in said space, which comprises, transmitting said programs as modulated carrier frequencies over the power system to feeder branch points thereof, amplifying said carrier frequencies and separately demodulating them near each branch point to obtain the respective modulations therefrom, and distributing said modulations from each branch point to a group of program receivers, the division of said receivers into groups being such that the number of receivers in a group is small relative to the total number of receivers in said space.

WILLIAM J. HERDMAN. 

